Headlight/Passing lights going out at times

I have a 96 Heritage. The headlamp and passing lamps will go out and then after a bit come back on.It does not seem to be short related. I turned the passing lamps off and the lights stayed on and did not go off again. I am not sure that this had anything to do with the lights staying on..
Anybody got any ideas. I checked all connections and found no obvious shorts. Could the problem be in the passing lamp switch or maybe the dim/bright switch? Thanks Roy-Ark

What I would do is to change the main circuit breaker. They get tired with age and loads and will trip earlier than they should at times when loaded. The heat of the engine and it's location will also have an effect on it too. It's a cheap part and can be bought at any auto parts store as long as it is the same physical dimensions and amperage as the one you removed.

The later baggers even upped the amperage of the breakers for a similar problem by 10 amps.